Method and system for monitoring a fluid system configured to operate with a filter

ABSTRACT

Systems and methods for monitoring a fluid system configured to operate with a filter are described herein. A differential pressure between an upstream position and a downstream position of a location of a filter is obtained. The differential pressure is compared to a differential pressure threshold. A maintenance action is detected when the differential pressure is below the differential pressure threshold and then a signal indicative that the maintenance action should be addressed is transmitted.

TECHNICAL FIELD

The present disclosure relates generally to fluid system monitoring,and, more particularly, to methods and systems for monitoring a fluidsystem configured to operate with a filter.

BACKGROUND OF THE ART

An engine is generally configured to operate with one or more filters.Each filter is used to filter a fluid, such as fuel, oil, hydraulic orair. The filter typically removes contaminants, such as impuritiesand/or residues, from the fluid. Once the filter gets clogged withcontaminants, the fluid no longer passes through the filter. A bypasscircuit can route the fluid around the filter when the filter isclogged. However, when the fluid with contaminants is allowed to flowinto the engine, this may result in damage to the engine. Other fluidsystems that operate with a filter may have similar problems.

As such, there is room for improvement.

SUMMARY

In one aspect, there is provided a method for monitoring an engineconfigured to operate with a filter. The method comprises obtaining adifferential pressure between an upstream position and a downstreamposition of a location of the filter, comparing the differentialpressure to a differential pressure threshold, detecting a maintenanceaction when the differential pressure is below the differential pressurethreshold and then transmitting a signal indicative that the maintenanceaction should be addressed.

In one aspect, there is provided a system for monitoring an engineconfigured to operate with a filter, the system comprises at least oneprocessing unit and a non-transitory computer-readable memory havingstored thereon program instructions. The program instructions areexecutable by the at least one processing unit for: obtaining adifferential pressure between an upstream position and a downstreamposition of a location of the filter, comparing the differentialpressure to a differential pressure threshold, detecting a maintenanceaction when the differential pressure is below the differential pressurethreshold and then transmitting a signal indicative that the maintenanceaction should be addressed.

In one aspect, there is provided a method for monitoring a fluid systemconfigured to operate with a filter. The method comprises obtaining adifferential pressure between an upstream position and a downstreamposition of a location of the filter, comparing the differentialpressure to a differential pressure threshold, detecting a maintenanceaction when the differential pressure is below the differential pressurethreshold and then transmitting a signal indicative that the maintenanceaction should be addressed.

In one aspect, there is provided a system for monitoring a fluid systemconfigured to operate with a filter, the system comprises at least oneprocessing unit and a non-transitory computer-readable memory havingstored thereon program instructions. The program instructions areexecutable by the at least one processing unit for: obtaining adifferential pressure between an upstream position and a downstreamposition of a location of the filter, comparing the differentialpressure to a differential pressure threshold, detecting a maintenanceaction when the differential pressure is below the differential pressurethreshold and then transmitting a signal indicative that the maintenanceaction should be addressed.

DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying figures in which:

FIG. 1 is a schematic cross-sectional view of an example gas turbineengine, in accordance with one or more embodiments;

FIG. 2 is a schematic of an example fluid circuit of a fluid system, inaccordance with one or more embodiments;

FIG. 3 is a flowchart illustrating an example method for monitoring afluid system, in accordance with one or more embodiments;

FIG. 4 is an example computing device for implementing a method and/orsystem for monitoring a fluid system, in accordance with one or moreembodiments.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

Systems and methods for monitoring a fluid system configured to operatewith a filter are described herein. In some embodiments, the system andmethods described herein are for monitoring an engine configure tooperate with a filter.

FIG. 1 illustrates a gas turbine engine 10 of a type that may beprovided for use in flight, generally comprising in serial flowcommunication a fan 12 through which ambient air is propelled, acompressor section 14 for pressurizing the air, a combustor 16 in whichthe compressed air is mixed with fuel and ignited for generating anannular stream of hot combustion gases, and a turbine section 18 forextracting energy from the combustion gases. Note that while the gasturbine engine 10 illustrated in FIG. 1 is a turbofan engine, themethods and systems described herein may also be applicable to turbopropengines, turboshaft engines, other types of aircraft engines and anyother suitable types of engines (e.g., industrial engines, automotiveengines, etc.). Other examples of engines comprise auxiliary power units(APUs), rotary engines, and hybrid electric propulsion engines.

With reference to FIG. 2, a fluid circuit of a fluid system is shown.The fluid system may be any suitable system that is configured tooperate with a filter for filtering a fluid that is to passtherethrough. In some embodiments, the fluid circuit is of an engine,such as engine 10. As illustrated, a filter 210 is to be positioned at alocation 212 of the fluid system (e.g., a location of the engine 10).While FIG. 2 is described herein with reference to the engine 10, thisis for example purposes only and the fluid circuit of FIG. 2 may be ofany suitable fluid system. A fluid F flows through the location 212 andany filter 210 located at the location 212. As used herein, the terms“upstream” and “downstream” are defined relative to a normal flowdirection of the fluid F. The fluid F may be fuel, a lubricant (e.g.,oil), hydraulic, air or any other suitable fluid. Accordingly, thefilter 210 may be a fuel filter, an oil filter, an air filter, alubricant filter, a hydraulic filter, or any other suitable fluidfilter. A differential pressure between an upstream position 222 and adownstream position 224 of the location 212 of the filter 210 can beobtained. In the embodiment illustrated in FIG. 2, the differentialpressure is obtained by use of a differential pressure sensor 250comprising a first sensor 232 at the upstream position 222 and a secondsensor 234 at the downstream position 224. The first sensor 232 measuresupstream pressure and the second sensor 234 measures downstreampressure. The differential pressure sensor 250 determines thedifferential pressure as a difference between the downstream pressureand the upstream pressure. The differential pressure sensor 250 providesthe differential pressure to a computing device 400. When no filter ispositioned at the location 212, the differential pressure issubstantially equal to zero, as the downstream pressure is substantiallyequal to the upstream pressure. When a filter 210 is positioned at thelocation 212, the differential pressure generally increases with time asthe filter 210 gets contaminated in time with impurities and/orresidues. If the filter 210 ruptures, the differential pressure woulddecrease from its previous value prior to the filter rupture. Thecomputing device 400 may accordingly monitor the differential pressurefor the purposes of detecting a maintenance action when the differentialpressure is below a differential pressure threshold. Detecting themaintenance action may comprise detecting that a missing filter is to beinstalled at the location 212, detecting that the filter 210 is rupturedand/or detecting any other suitable maintenance action.

In alternative embodiments, a first sensor 232 and a second sensor 234provides the upstream pressure and the downstream pressure directly tothe computing device 400 for determining the differential pressure andthe differential pressure sensor 250 may be omitted. In someembodiments, the computing device 400 may be provided as part of theengine 10 or may be external to the engine 10. The differential pressuresensor 250 and/or the sensors 232, 234 may be provided as part ofexisting sensors provided by the engine 10 or may be added to the engine10 for the purposes of obtaining the differential pressure. In otherwords, the sensors 250, 232, and/or 234 may be provided as part of thefluid system or may be external to the fluid system.

With reference to FIG. 3, there is shown a flowchart illustrating anexample method 300 for monitoring a fluid system, such as of the engine10 of FIG. 1. While the method 300 is described herein with reference tothe engine 10 of FIG. 1, this is for example purposes only. The method300 may be applied to any suitable engine and/or to any suitable fluidsystem configured to operate with a filter. The method 300 may beimplemented by the computing device 400.

At step 302, a differential pressure between an upstream position 222and a downstream position 224 of a location 212 of a filter 210 isobtained. In some embodiments, the differential pressure is obtained byreceiving differential pressure measurements from a differentialpressure sensor 250. The differential pressure sensor 250 may be an oilfilter differential pressure sensor, a fuel filter differential pressuresensor, or any other suitable differential pressure sensor. Thedifferential pressure sensor 250 may be located in the fuel system, oilsystem, or air system of the engine 10. The differential pressure sensor250 may be a dual-channel pressure transducer. In some embodiments, thedifferential pressure is obtained by receiving an upstream pressuremeasurement at the upstream position 222 from a first sensor 232,receiving a downstream pressure measurement at the downstream position224 from a second sensor 234, and determining the differential pressureas a difference between the downstream pressure measurement and theupstream pressure measurement. The first and second sensors 232, 234 maybe fuel pressure sensors, oil pressure sensors, air pressure sensors orany other suitable sensors. In some embodiments, the differentialpressure is obtained by receiving the differential pressure from anaircraft or engine computer. In some embodiments, the differentialpressure is obtained by receiving the upstream pressure and thedownstream pressure from an aircraft or engine computer and determiningthe differential pressure from the upstream pressure and the downstreampressure. The differential pressure (or the upstream pressure and thedownstream pressure) may be obtained in real-time, near real-time, orwhenever the differential pressure is needed and/or may be recorded inaccordance with any suitable time interval or may be recordedirregularly.

At step 304, the differential pressure is compared to a differentialpressure threshold. The differential pressure threshold may bepredetermined or may be determine during the performance of the method300. The comparison of the differential pressure to the differentialpressure threshold may be performed in real-time for the purposes ofmonitoring the engine 10 in real-time while the engine 10 is operating.

At step 306, a maintenance action is detected when the differentialpressure is below the differential pressure threshold. When themaintenance action is detected, a signal indicative that the maintenanceaction should be addressed is transmitted. For example, the signal maybe transmitted to a display device to display an alert of themaintenance action or transmitted to a computer (e.g., an aircraftcomputer) communicatively coupled to a display device to cause thedisplay device to display an alert of the maintenance action. This mayallow for real-time monitoring of an aircraft engine while the aircraftis inflight. By way of another example, the signal may be transmitted toan on-ground computer in order to alert ground crew or other suitableperson of the maintenance action. The term “on-ground computer” refersto a computer that is not on an aircraft that comprises the engine 10.The on-ground computer may be communicatively coupled to a displaydevice to cause the display device to display an alert of themaintenance action. The alert may be a light or a text message in anaircraft cockpit or elsewhere on or off the aircraft. The alert mayindicate the type of maintenance action (e.g., a ruptured filter needsto be replaced, a missing filter is to be installed, etc.). The signalmay be transmitted to any other suitable electronic device or computer.

The method 300 may be for detecting when a filter is ruptured.Accordingly, in some embodiments, detecting the maintenance action atstep 306 comprises detecting that the filter 210 is ruptured. A rupturedfilter refers to a filter having a break, tear or hole that allows thefluid to pass through the break, tear or hole in the filter. The method300 may further comprise determining the differential pressure thresholdbased on at least one previous differential pressure measurement betweenthe upstream position 222 and the downstream position 224 of thelocation 212 of the filter 210. Accordingly, determining thedifferential pressure threshold may comprise setting the differentialpressure threshold based on a highest recorded previous differentialpressure measurement. The highest recorded previous differentialpressure measurement may be obtained according to a rolling maximum ofthe obtained differential pressure at step 302. That is, thedifferential pressure obtained at step 302 may be recorded and/ortracked in real-time to determine the highest recorded previousdifferential pressure measurement.

The differential pressure threshold may be set at the highest recordedprevious differential pressure measurement minus an offset. The offsetmay be a predetermined value or may be determined during the performanceof the method 300. For example, the offset may be set at a percentage orother function of the highest recorded previous differential pressuremeasurement. The offset may be set based on an expected decrease inpressure when a filter rupture occurs. The expected decrease in pressuremay be determined by recording the differential pressure when a filterrupture occurs. The expected decrease in pressure may correspond to anaverage of a plurality of differential pressure measurements of arupture of one or more filters. The offset would typically be set suchthat it would be larger than differential pressure variations in normaloperation of the engine 10.

In some embodiments where the fluid is oil, and a chip detector may beused to confirm filter rupture by way of correlation, as a rupturedfilter would create more contamination in the oil system and the chipdetector may indicate higher contamination. However, depending on thesize of the filter hole when it is ruptured, there may be insufficientcontamination to trigger the chip detector and thus absence of chipdetector indication is not necessarily indicative of absence of filterrupture.

It should be appreciated that by monitoring the fluid system to detectwhen the filter 210 is ruptured may allow for early failure detection ofthe filter 210 and/or may allow for the service life of the filter 210to be extended.

The method 300 may be for detecting when a filter is missing. A missingfilter refers to no filter being installed at the location 212 for thefilter. Accordingly, in some embodiments, detecting the maintenanceaction at step 306 comprises detecting that a missing filter is to beinstalled at the location 212 for the filter. In some embodiments, thedifferential pressure threshold is predetermined based on an expecteddifferential pressure of a new filter. The expected differentialpressure of the new filter may be determine by recording thedifferential pressure when a new filter is installed in the location212. The expected differential pressure of the new filter may correspondto an average of a plurality of differential pressure measurements ofone or more new filters.

In some embodiments, the method 300 further comprises starting a timerwhen the differential pressure drops below the differential pressurethreshold and detecting the maintenance action when the timer exceeds apredetermined period of time. The timer would be reset if thedifferential pressure exceeds the differential pressure threshold beforethe timer exceeds the predetermined period of time.

During engine transient conditions, the fluid pressure (e.g., oilpressure or fuel pressure) may increase or decrease. Accordingly, themethods and systems described herein may be able to differentiatebetween the effect of a commanded set point and the change in pressuredue to contamination or rupture of the filter 210. In some embodiments,the method 300 comprises detecting when the engine 10 is operating in atransient condition and correcting the differential pressure obtained atstep 302. The differential pressure may be corrected based on one ormore engine operating parameters. The engine operating parameter(s) maycomprise one or more of: engine speed (e.g. N2 speed); pressure (e.g.,main oil pressure (MOP)); temperature (e.g., main oil temperature(MOT)); and any other suitable parameter(s). The parameter(s) selectedmay be sampled such that each parameter is indicative of a steady statefor that parameter, rather than a transient value, which may not berepresentative of that parameter's true value.

With reference to FIG. 4, the method 300 may be implemented using acomputing device 400 comprising a processing unit 412 and a memory 414which has stored therein computer-executable instructions 416. Theprocessing unit 412 may comprise any suitable devices configured toimplement the system such that instructions 416, when executed by thecomputing device 400 or other programmable apparatus, may cause thefunctions/acts/steps of the method 300 as described herein to beexecuted. The processing unit 412 may comprise, for example, any type ofgeneral-purpose microprocessor or microcontroller, a digital signalprocessing (DSP) processor, a central processing unit (CPU), anintegrated circuit, a field programmable gate array (FPGA), areconfigurable processor, other suitably programmed or programmablelogic circuits, or any combination thereof.

The memory 414 may comprise any suitable known or other machine-readablestorage medium. The memory 414 may comprise non-transitory computerreadable storage medium, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Thememory 414 may include a suitable combination of any type of computermemory that is located either internally or externally to device, forexample random-access memory (RAM), read-only memory (ROM), compact discread-only memory (CDROM), electro-optical memory, magneto-opticalmemory, erasable programmable read-only memory (EPROM), andelectrically-erasable programmable read-only memory (EEPROM),Ferroelectric RAM (FRAM) or the like. Memory 414 may comprise anystorage means (e.g., devices) suitable for retrievably storingmachine-readable instructions 416 executable by processing unit 412. Insome embodiments, the computing device 400 can be implemented as part ofa full-authority digital engine controls (FADEC) or other similardevice, including electronic engine control (EEC), engine control unit(ECU), and the like.

The methods and systems for monitoring a fluid system described hereinmay be implemented in a high level procedural or object orientedprogramming or scripting language, or a combination thereof, tocommunicate with or assist in the operation of a computer system, forexample the computing device 400. Alternatively, the methods and systemsfor monitoring a fluid system may be implemented in assembly or machinelanguage. The language may be a compiled or interpreted language.Program code for implementing the methods and systems for monitoring afluid system may be stored on a storage media or a device, for example aROM, a magnetic disk, an optical disc, a flash drive, or any othersuitable storage media or device. The program code may be readable by ageneral or special-purpose programmable computer for configuring andoperating the computer when the storage media or device is read by thecomputer to perform the procedures described herein. Embodiments of themethods and systems for monitoring a fluid system may also be consideredto be implemented by way of a non-transitory computer-readable storagemedium having a computer program stored thereon. The computer programmay comprise computer-readable instructions which cause a computer, orin some embodiments the processing unit 412 of the computing device 400,to operate in a specific and predefined manner to perform the functionsdescribed herein.

Computer-executable instructions may be in many forms, including programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Typically the functionality of the program modulesmay be combined or distributed as desired in various embodiments.

The above description is meant to be exemplary only, and one skilled inthe art will recognize that changes may be made to the embodimentsdescribed without departing from the scope of the invention disclosed.Still other modifications which fall within the scope of the presentinvention will be apparent to those skilled in the art, in light of areview of this disclosure.

Various aspects of the methods and systems for monitoring a fluid systemmay be used alone, in combination, or in a variety of arrangements notspecifically discussed in the embodiments described in the foregoing andis therefore not limited in its application to the details andarrangement of components set forth in the foregoing description orillustrated in the drawings. For example, aspects described in oneembodiment may be combined in any manner with aspects described in otherembodiments. Although particular embodiments have been shown anddescribed, it will be obvious to those skilled in the art that changesand modifications may be made without departing from this invention inits broader aspects. The scope of the following claims should not belimited by the embodiments set forth in the examples, but should begiven the broadest reasonable interpretation consistent with thedescription as a whole.

What is claimed is:
 1. A method for monitoring an engine configured tooperate with a filter, the method comprising: obtaining a differentialpressure between an upstream position and a downstream position of alocation of the filter; comparing the differential pressure to adifferential pressure threshold; detecting a maintenance action when thedifferential pressure is below the differential pressure threshold andthen transmitting a signal indicative that the maintenance action shouldbe addressed.
 2. The method of claim 1, wherein detecting themaintenance action comprises detecting that the filter is ruptured. 3.The method of claim 2, further comprising determining the differentialpressure threshold based on at least one previous differential pressurebetween the upstream position and the downstream position of thelocation of the filter.
 4. The method of claim 3, wherein determiningthe differential pressure threshold comprises setting the differentialpressure threshold based on a highest recorded previous differentialpressure.
 5. The method of claim 1, wherein detecting the maintenanceaction comprises detecting that a missing filter is to be installed atthe location for the filter.
 6. The method of claim 5, wherein thedifferential pressure threshold is predetermined based on an expecteddifferential pressure of a new filter.
 7. The method of claim 6, whereinthe expected differential pressure of the new filter corresponds to anaverage of a plurality of differential pressure measurements of one ormore new filters.
 8. The method of claim 1, further comprising startinga timer when the differential pressure drops below the differentialpressure threshold and detecting the maintenance action when the timerexceeds a predetermined period of time.
 9. The method of claim 1,wherein obtaining the differential pressure comprises receivingdifferential pressure measurements from a differential pressure sensor.10. The method of claim 1, wherein the filter is an oil filter or a fuelfilter.
 11. A system for monitoring an engine configured to operate witha filter, the system comprising: a processing unit; and a non-transitorymemory communicatively coupled to the processing unit and comprisingcomputer-readable program instructions executable by the processing unitfor: obtaining a differential pressure between an upstream position anda downstream position of a location of the filter; comparing thedifferential pressure to a differential pressure threshold; detecting amaintenance action when the differential pressure is below thedifferential pressure threshold and then transmitting a signalindicative that the maintenance action should be addressed.
 12. Thesystem of claim 11, wherein detecting the maintenance action comprisesdetecting that the filter is ruptured.
 13. The system of claim 12,wherein the computer-readable program instructions are furtherexecutable by the processing unit for determining the differentialpressure threshold based on at least one previous differential pressurebetween the upstream position and the downstream position of thelocation of the filter.
 14. The system of claim 13, wherein determiningthe differential pressure threshold comprises setting the differentialpressure threshold based on a highest recorded previous differentialpressure.
 15. The system of claim 11, wherein detecting the maintenanceaction comprises detecting that a missing filter is to be installed atthe location for the filter.
 16. The system of claim 15, wherein thedifferential pressure threshold is predetermined based on an expecteddifferential pressure of a new filter.
 17. The system of claim 16,wherein the expected differential pressure of the new filter correspondsto an average of a plurality of differential pressure measurements ofone or more new filters.
 18. The system of claim 11, wherein thecomputer-readable program instructions are further executable by theprocessing unit for starting a timer when the differential pressuredrops below the differential pressure threshold and detecting themaintenance action when the timer exceeds a predetermined period oftime.
 19. The system of claim 11, wherein obtaining the differentialpressure comprises receiving differential pressure measurements from adifferential pressure sensor.
 20. A method for monitoring a fluid systemconfigured to operate with a filter, the method comprising: obtaining adifferential pressure between an upstream position and a downstreamposition of a location of the filter; comparing the differentialpressure to a differential pressure threshold; detecting a maintenanceaction when the differential pressure is below the differential pressurethreshold and then transmitting a signal indicative that the maintenanceaction should be addressed.